Grinding device



Dec. 11, 1956 A. DE MARCHI GRINDING DEVICE 2 Sheets-Sheet J Filed July 26, 1954 E FICE z FIE.' S

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A. DE MARCHI GRINDING DEVICE Dec. 11, 1956 United States Patent() GRINDING DEVICE Arturo De Marchi, Minneapolis, Minn.

Application July 26, 1954, Serial No. 445,781

3 Claims. (Cl. 51--176) This invention relates to an improved grinding device for grinding and polishing a surface, such as a oor surface of terrazzo. This invention relates particularly to dry grinding such a surface. The applicant believes that there is no dry grinding device available for use at the present time which eifectively carries away by suction all of the dust created by the grinding operation. The raising and spreading of dust as a result of the grinding operation is particularly damaging in doing interior work and it is timeconsuming and costly to clean up said dust. In an eifort to avoid creating and spreading dust a wet grinding device is generally used, but this type of grinding is inconvenient to handle by the operators and this is a more costly operation than would be a dry grinding method of operation.

It is therefore an object of this invention to provide a dry type of surface grinding device which is adapted to carry away by suction all of the dust which is created and raised by the grinding operation.

It is another object of this invention to provide a dry type of surface grinding device comprising a grinding member, a hood overlying a substantial portion of said member, a conduit having suction therein connected to said hood to draw air currents therethrough, and means in said hood for directing air currents to carry away all of the dust created by the grinding operation and particularly concentrating such air currents at the end portions of said grinding device to prevent the escape of any dust at said ends.

It is a further object of this invention to provide a type of surface grinding device comprising a grinding member, a hood overlying a substantial portion of said member and extending beyond the ends thereof, a conduit having suction therein connected to said hood for drawing air currents therethrough, and means in said hood for directed air currents to act at the end portions of said member.

It is a more specic object of this invention to provide a dry type of surface grinder comprising a housing having a motor therein, a grinding member adjacent said housing, a shaft having said grinding member secured thereto and being driven by said motor, a hood carried by said housing overlying a substantial portion of said grinding member and extending beyond the ends thereof, a conduit having suction therein connected to said hood to draw air currents therethrough, and a bale in said hood to direct said air currents to cause strong air currents into said hood adjacent the end portions of said grinding member.

With reference to the structure set forth in the preceding paragraph, it is also an object of this invention to provide a slidable spring repelled portion at one end of said hood whereby under pressure said portion may be moved inwardly to uncover an end portion of said grinding member whereby said grinding member can be positioned directly adjacent a vertical wall or adjacent a riser, as on a stairway.

These and other objects and advantages of the invention will be fully set forth in the following description made in connection with the accompanying drawings in which like reference characters refer to similarI parts throughout the several views and in which:

Fig. 1 is a top plan view of applicants device showing some portions in dotted lines;

Fig. 2 is a view in front elevation taken on line 2-2 of Fig. 1, as indicated by the arrows;

Fig. 3 is a top plan view with a portion broken away and some parts shown in dotted lines;

Fig. 4 is a view in side elevation; and

Fig. 5 is a partial view in horizontal section taken on line 5 5 of Fig. 4, as indicated by the arrows.

Referring to the drawings, and particularly to Figs. l and 3, a housing 10 is shown having a central body portion 10a. Said portion 10a is here illustrated as being generally cylindrical in form and is preferably made of a sheet metal material. Said housing 10 has a rear end portion of reduced diameter flared outwardly to form a ange 10b. Secured to said flange and extending outwardly therefrom is a tapering sleeve 10c of substantial length. Said sleeve will be made preferably of a rigid material, such as sheet metal, and forms a rear handle for holding applicants device. Said housing 10 has a forwardly extending cylindrical portion 10d of reduced diameter. Said portion 10d has secured to its outer end a cylindrical portion 10e extending at right angles thereto.

Mounted in portion 10a is a motor 1ll and the same is preferably an electrical motor. Said motor has a drive shaft 11a which extends for some distance into portion 10d. A conduit 12 is shown which will be disposed through portion 10c and connected at one end to said motor to provide current for its operation. Said conduit 12 will be connected at its other end to a suitable source of electrical energy. A switch 13 is secured in said portion 10c by a screw 14, and said switch will control the ow of power from said conduit 12 to said motor 11.

Mounted in portion 10d is a shaft 17 journaled in cage type of ball bearings 18 and 19. The inner end of said shaft 17 has secured thereto a spur gear 22 which is driven by a gear 23 secured to said end portion of said shaft 11a. Said last two mentioned gears are of Well known construction and are here shown only in dotted lines. Disposed in portion 10e and extending outwardly at one end therefrom for some distance is a shaft 25. Said shaft is journaled in bearings 26 and 27 carried in the end portions of said portion 10e. Said bearing 26 is shown as comprising a double cage type of bearing and member 27 is shown as comprising a single cage type of bearing. A beveled gear 29 is secured to the outer end of said shaft 17 by a pin 29a. A beveled gear 31 is secured to shaft 25 by a pin 31a and is engaged and driven by said gear 29. A cap screw 34 is threaded into one end of said portion 10e to close said end. A grinding member 36 is carried on the extended end portion of said shaft 25. This is a standard type of a grinding member here shown as being cylindrical in form and having an outer portion 36a which may be formed of carborundum, and it is shown here as having an inner sleeve 36b which may be formed of any suitable material, such as sheet metal. The inner end of said member 36 is provided with a collar 38 having a bore of substantially the same diameter as that of said member 25 and is secured to said member 25 by a locking member 38a. Said member 36 extends outwardly of said shaft 25 for a short distance and is secured thereto adjacent its outer end by a nut 40 which is threaded onto the end portion of said shaft 25.

A conduit 45 is provided having an elongated tubular portion 45a carried by said housing 10 and secured thereto by a tube clamp 47. Said tube clamp is integral with said housing 10 and may be secured thereto in any suitable manner, such as by welding. Said tube clamp comprises and upper portion 47a and a lower portion 47b. Said member 47 is bored to have a diameter somewhat less than the outside diameter of -portion 45a. A screw 50 is threaded into the outer side portions of members 47a and llb and a sliding bar 50a is slidable throug'hwthe wp puritan cfsaidscrew so and will be t dfn) aratv said portions 47a and 47b'to tightentlimaboutsaid'portion 45a. Extending `forwa'rtlly 4of v'said V'portion .452i a portion 45h which is widened lto form a hood 'to 'extend substantially the full length `of `'said ineinberl d'arid r`being just short ofthe daterend thereof. 'Said portieiritl'b is substantially V-shaped vin vertical "section V:and overlies a substantial portion vof the :width of "s'aidmember 3*'6 and is here shown overlying substantially one-half the width of Said-member a6. rf desires, said naad may searranged to vcover agreater `'portion o f saidgrintlng inem ber 36. Carried by said :portion "45o at the daterend of said member 36 -is aportion 45e forming ian lextension of saidfportion 45h and 'extending beyond tlieend'of said member 36 for 'some distance.A A"Said-member "l'lrjlrlas its upper and lower ends reversely Lcurved. The :upper curved end portion is recessed somewhat, 'as shown in Fig. 5. ASaid lportion 45C has its upper kand lower ends reversely 'curved about said curved "portions of portion t)i517 to be movable longitudinally thereof. Secured in the upper curved portion of portion 45e isa coiled spring 53. One end portion of said spring 53g will bear against the inner end of said upper recessed curved 'end portion of member 45, and its other end will bear against lthe outer end of the tipper curved portion of fmember 45e. Said outer end will have a vllange 45d to form alst'op for said spring. When portion 45o is moved inwardly, said spring will be compressed and whenfpress't'tre 'against member 45e is removed, said spring willmove saidlp'ortion 45a outwardly. Normally, portion 45e will extend for a short distance overthe end of 'member '36. v Connected to the rear end portion of member 4S is -a vccinduit 54 and said conduit is here disclosed as being Amade of tlexible material and vwill be preferably connected to a dust collector (not shown). `Said member S4 is 'secured to portion 45a by a collar 55. Said dust collector not here shown will be provided with means for, creating suction in said conduit 54 and 'therethrough in hood 45. Such dust colllectors are 'not well jkn'own in the "art and it is believed need no further description or illustration. n Disposed centrally in said portion 45h is a baffle `member 53. Said ba-le member'is here 'shown as being sonrewhat diamond-shaped in horizontal section `and -it jextends from the bottom to the top portion of said metnb'erft'e'b and is secured theretoin'any suitable manner, such as by welding. The rear sides 58a and 58h fof said member S8 are substantially lparallel to the sides of said portion 5b. The rearward portion of said baille Y5'8 is somewhat longer than its front portion. y i y Secured to said portion '10e and upstnding for sonre distance therefrom is a member 60 and it may be secured to said member 10e in any `suitable manner, 'as by weiding. A handle 61 is provided having one end portion secured to member 60 and extending longitudinally for some distance along theou'ter `e'nd portion of said shaft A25. Secured to the under 'sides of vsaid hood '45b and portion 10d are supporting 'members 63.v `Said members 63 will raise upwardly somewhat vthe outer end portion of applicants device when it is not in use and is placed in a horizontal position. Y y l l'n operation, applicants device will be held by having the operator place one hand about handle 61 'andthe other hand about handle portion 10c. Conduit 12 will be connected to a source of Velectrical current. Conduit S4 will normally be connected to "a 'dust collector having therein means for creating 'suction in conduit 54 and therethrough in said hood 451g. Said switch y13 is easily Vreached by the voperatorvfor controlling motor 11,which motor drives shafts `17 and 2 5 and ygriding wheel 36. ,In grinding and polishing a terrazzosurface thedoperator will place grinding wheel '36 against said surface and 'turn on switch 13 to operate motor 11. At the saine 'time said means in said dust collector will be turned on to create suction in member 45 and withdraw dust created by the grinding process through hood 45'!) and conduit 54. Said hood 4511' extends over the outer edge portions of grinding member 36, and as here shown extends over one-half of its width. Disposed within member 45, is a baille 58 designed to direct 'the lindrawn air currentes to particularly concentrate and intensify them at the outer sides of portion 45C and at the outer edge portions of said member 36. It` has been found in practice that a substantial portion ofthe dust raised from theA grinding process is raised at the outer edge portions 'of the grinding member and it is found in actual practice that the outer that the outer edge portions of said grinding membcr are in use more of the time than the central portion thereof. A substantial amount of the dust raised from the grinding processhas been found to escape at the edge portions of the grinding member. Appl'icants hood and the baffle within it are particularly designed and adapted to be most effective in withdrawing andcap'turing all of the dust at the :edge portions of said grinding member 35.

VIn grinding a horizontal surface adjacent a vertical wall or in grinding a'step` on a stairway adjacent a riser7 said grinding wheel 36 can be placed directly against the verticalrsu'rface jandgpressure against said vertical 'surface will push memberr45c inwardly against spring 53 to expose the end portion of said grinding 'member 36 to permit-grinding and polishing of thehorizontal surface directly 'up to the vertical surface. When applicants de`- vice is rnovjed laway kfrom said vertical surface, said spring 53 will return said member 45C to 'its normal position extending lover the end portion of member 36. When applicants device is not in use it may be rested on supporting member 63 fand the rearward portion of said device. Said supporting members 63 are of sulhcient height to raisesaid grinding member 36 above the surface Vupon which said device is resting.

Thus it is seen that I have provided a compact grind- 4ing device easily handled by a single operator and adapted to completely carry away all of the Vdust raised in a dry grinding process of grinding and polishing terrazzo. Applicants 'device is particularly effective in preventingrthe escape of any dust at the edge portions of the grinding member. Applicants device has been thoroughly tested and found to be very efcient in operation and very effective in capturing and carrying away all the -dust raised in the grinding operation. i It will of course be understood that various changes may be made in the form, details, arrangement and proportions of the parts, without departing from the scope of applicants invention, which, generally stated, consists in a deviceA capable of carrying out the objects above set forth, in the parts and combinations of parts disclosed and defined in the appended claims.

What is claimed is: n

l. A `portable grinding device for polishing a terrazzo surface having in combination, a housing, an elongated cylindrical grinding member ycarried at one end of said housing and extending ina direction at right angles to the 'axis thereof, a conduit in lwhich suction is created having a portion clamped to lsaid housing, a hood connected to said conduit `adjacent said housing and substantia'lly `V-shaped in vertical longitudinal section and having sides diverging to a width substantially the wid-th of said grinding member and then having portions entending in the direction of said grinding member at right angles to the axis thereof, said hood extending above `and Ibelow said grinding member for Vsome distancethereacross, arba'fliezmeinber substantially diamond-shaped in form positionedcentrally transversely in said hood and extending 'the full height thereof, said baliie `member being adjacent ysaid grinding member in operating position and having its sides remote from said grinding member parallel to the 'diverging sides of said hood and forming channels therewith, whereby said hood withdraws dust the full Width of said grinding member and said channels direct indrawn currents Ior air to be particularly intensified at the cnd portions of said grinding member.

2. A portable grinding device for polishing a terrazzo surface having in combi-nation, a housing, an elongated cylindrical grinding member carried at one end of said housing and extending in a direction at right angles to the axis of said housing, means carried in said housing for operating said grinding member and means connecting said last mentioned means to a source of power, a condui t in `which suction is produced having a portion adjacent the central portion of said housing and being removably secured thereto, a hood connected to said conduit, said hood being substantially V-shaped in vertical longitudinal section and having side walls diverging from `said conduit in the direction of said grinding member to a width substantially the width `of said grinding member and having portions extending above and below said grinding member for some distance thereacross, a baille member substantially diamond-shaped in plan disposed substantiallyl centrally transversely of said hood and extending the full height thereof and being positioned 'to be substantially adjacent said grinding member when in operating position, the sides of said 'bathe member remote from the outer end of said hood being respectively parallel to the diverging sides of said hood forming channels therewith, whereby in operation said hood will ldraw in dust the full width of said grinding wheel and said channels will concentrate and intensify the indrawn currents of air adjacent the ends of said grinding member.

3. A portable grinding d-evice for polishing a terrazzo surface having in combination, a housing having a central portion generally cylindrical in form having `a rear end portion of substantially reduced diameter tapering to form a handle and having a front end portion of reduced transverse dimension, an elongated cylindrical grinding member mouted on said front end portion and extending in a direction 'at right angles to the axis of said housing, a handle secured at one end 'to said front end portion of said housing and having its other end extend over and being spaced above `said grinding member, means in said housing for rotating said grinding member, and means connecting said last mentioned means to a source of power, a conduit in which suction is produced having a portion longitudinally of and adjacent the central portion of said housing, a clamping member securing said conduit to Isaid housing, a hood having one -end connected to an end `of said conduit, said hood being V-shaped in vertical longitudinal section and having sides diverging to a width substantially 'the Width of said grinding member, said sides having portions extending at right angles to the axis of said grinding member and said hood having portions extending above and below said grinding member for some distance thereacross substantially the full width thereof, a bafe member substantially diamond-shaped in plan disposed substantially centrally transversely or" said hood and extending the full height thereof, said 'bafe member being positioned to be adjacent said grinding member when in operating position and having its sides Y Vremote from said grinding member parallel lto the diverging sides of said hood forming channels therewith, whereby in operation said hood is adapted to ldraw in dust `the full width of said grinding member and said channels direct the indrawn air to intensify it at 'the ends of said grinding member to draw in substantially all of the `dust raised by the operation of said grinding member.

References Cited in the le of this patent UNITED STATES PATENTS 

